Bromoperoxidase from the marine snail, Murex trunculus

Abstract

1. 1. Extracts of a 25,000 g sediment of Murex trunculus hypobranchial gland homogenate contain an enzyme which brominates monochlorodimedon in the presence of bromide and H 2O 2. 2. 2. Dependence of activity on H 2O 2 concentration exhibits a sharp optimum which increases from 20 μM at pH 7.4 to 400 μM at pH 4.0. 3. 3. Dependence on Br − concentration follows a simple saturation curve with K m values of 7 mM at pH 7.4 and 30 mM at pH 5.0. 4. 4. The pH optima depend on H 2O 2 concentration, ranging from pH 6.6 at 10 μM to pH 4.8 at 200 μM. 5. 5. The enzyme is totally inactive with Cl − and F −, although both these ions inhibit bromination.